This seems to be a misunderstanding of polling, of models built on polling, and maybe on statistics in general. There was some polling error in 2016, it's true

This seems to be a misunderstanding of polling, of models built on polling, and maybe on statistics in general. There was some polling error in 2016, it's true, in several states that turned out to be determinative. Uncertainty can be and is built into models based on the quality and frequency of state polls, and 538's model certainly takes the polling errors of 2016 into account by adding more uncertainty to states and pollsters which got 2016 wrong. That said, most of the shifts in state results were within the margin of polling error, which is why Silver's model gave Trump a much higher chance of winning than any other major models did.